Ductility of Structural Steel Members Governed by Fracture

受断裂控制的钢结构构件的延展性

• 批准号: 04402041
• 负责人: KUWAMURA Hitoshi
• 金额: $ 26.82万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04402041/
• 关键词: Steel Structures; Fracture; Plastic Deformation; Safety; Earthquake Resistance; 建築鋼構造; 塑性; き裂; 耐風設計

1. Experimental Simulation of Fracture in Large-Scale TestingFracture test was done by using cold-formed square steel tubes. It was found that the fracture process is composed of crack initiation, crack penetration, and final fracture. The mechanical properties represented by uniform elongation and Charpy impact value have a significant influence on the fracture.2. Crack Initiation StrainFrom fracture testing, in which material strength, welding condition, notch shape, size, and loading program are changed, it was found that the crack initiation strain is governed by the uniform strain pertinent to the material. Furthermore, the fact is useful for practice that the crack initiation strain is not affected by size.3. Seismic Performance of Structures Having Brittle ColumnsDynamic response analysis of steel frames having brittle columns showed that such frames have the risk of dynamic progressive failure. In order to avoid the failure, the frame should be assigned more strength than ordinary ductile frames, and the strength amplification factor is proposed.4. Design GuideDesign guide to avoid brittle fracture in steel structures during a big earthquake is established on the basis that the fracture is conservatively predicted by the crack initiation.

1.大型试验中断裂的实验模拟采用冷弯方钢管进行了断裂试验。结果表明，断裂过程由裂纹萌生、裂纹穿透和最终断裂组成。以均匀延伸率和夏比冲击值为代表的力学性能对试样的断裂伸长率有显著影响.启裂应变从断裂试验中，材料强度，焊接条件，切口形状，尺寸和加载程序的变化，发现启裂应变是由有关材料的均匀应变。此外，裂纹萌生应变不受尺寸影响的事实对实践是有用的.脆性柱结构的抗震性能脆性柱钢框架的动力响应分析表明，此类框架具有动力渐进破坏的危险性。为了避免框架的破坏，应赋予框架比普通延性框架更大的强度，并提出了强度放大系数.设计指南避免钢结构在大地震中发生脆性断裂的设计指南是建立在通过裂纹萌生保守预测断裂的基础上的。

项目成果

桑村仁: "冷間プレス曲げによる鋼板の材質変化とその改善に関する研究" 日本建築学会構造系論文報告集. 444. 125-133 (1993)

桑村仁：“冷压弯曲引起的钢板材质变化及其改善的研究”日本建筑学会结构工程学论文报告444. 125-133（1993）

桑村 仁: "延性き裂発生ひずみに及ぼす冷間塑性加工の影響" 日本建築学会構造系論文報告集. 454. 171-178 (1993)

Hitoshi Kuwamura：“冷塑性加工对延性裂纹萌生应变的影响”日本建筑研究所结构科学论文集 454. 171-178 (1993)。

Kuwamura,Hitoshi: "Brittle Fractuve under Repeated High Stresses" Journal of Constructional Steel Research. 29. 5-19 (1994)

Kuwamura，Hitoshi：“重复高应力下的脆性断裂”建筑钢研究杂志。

桑村 仁: "延性き裂発生ひずみに及ぼす寸法の影響" 日本建築学会構造系論文集. 458. 119-125 (1994)

Hitoshi Kuwamura：“尺寸对延性裂纹萌生应变的影响”日本建筑学会结构工程论文集 458. 119-125 (1994)。

Kuwamura, Hitoshi: "Experiment on the mechanical properties and their improvement of cold roll-formed steel columns" Journal of Struct.Constr.Engng., AIJ. No.453. 171-180 (1993)

Kuwamura, Hitoshi：“冷弯成型钢柱的机械性能及其改进实验”Journal of Struct.Constr.Engng.，AIJ。